PHILADELPHIA — No scientific experiment — except, perhaps, the detonation of the first atomic bomb — is more familiar to the public than Benjamin Franklin's legendary kite experiment.
As famously depicted by numerous artists, Franklin and a boy fly a kite in a field during a terrible thunderstorm. Lightning strikes the kite and an arc of electricity flies from a key on the kite string to Franklin's finger.
Eureka! Franklin "discovers" electricity.
But as next month's (June) 250th anniversary of the experiment approaches, questions remain whether it was a true scientific advance, a meaningless stunt or historical hogwash.
Simplistic portraits of the experiment may underlie doubts about its reality and importance, said Claude-Anne Lopez, author of several books on Franklin. For instance, a lightning strike would have killed or seriously injured both Franklin and the boy. And the individual depicted as a small boy actually was Franklin's 21-year-old son, William.
"Franklin was an amazing individual," Lopez said. "Statesman, philosopher, author, bon vivant, newspaper publisher, revolutionary, businessman, a kid who was taken out of school at age 10, ran away from home and learned everything he knew from reading. Maybe the idea that he also was a brilliant scientist just strains the limits of belief."
"The kite experiment was quite real," said H. W. Brands Jr., a historian at Texas A&M University and author of "The First American: The Life and Times of Benjamin Franklin." "Historians of science today still consider his work among the most significant of the 18th century. For this experiment, and related work, he received the era's equivalent of the Nobel Prize and was hailed as one of the great scientists of the age."
However, the experiment did not make Franklin the discoverer of electricity.
The ancient Greeks knew about electricity. Thales of Miletus, who died around 546 B.C., discovered that static electricity could be made by rubbing amber with wool. The word "electron" originated in a Greek word for amber.
And scientists in Europe had experimented with electricity long before Franklin.
Biographers say Franklin became interested in the nature of electricity in 1746 after reading about experiments done in Europe.
In Franklin's day, scientists were struggling to understand basic principles of electricity, such as attraction and repulsion. Franklin did coin the contemporary terms for the types of attraction — positive and negative. He introduced other common electrical terms such as "battery," "plus" (for positive charges), "minus" (for negative charges), "electrician," "electrified" and "charge."
Franklin turned his home in Philadelphia into an electrical laboratory, using instruments made from household items. He brought electricity into the house dangerously — via a wire leading from an iron rod attached to the chimney.
"On the staircase opposite my chamber door, the wire was divided, the ends separated about 6 inches, a little bell on each end," Franklin wrote in one letter to friend and fellow inventor Peter Collinson in London.
Franklin's famous electric bells signaled when electricity was in the atmosphere and available for use in his experiments. Franklin described huge arcs of electricity, as thick as his index finger, which lit up the staircase like bright sunlight.
The gadgets terrified Franklin's wife, Deborah, who wanted to disconnect the electric bells.
One experiment was nearly fatal. While trying to kill a turkey by electrocution, Franklin accidentally shocked himself. He blamed the mistake on houseguests who distracted him. The shock threw Franklin to the floor, where he flopped in convulsions.
"In the beginning, electricity was a game, a parlor trick," Lopez explained. "They had traveling electricians who amused people with demonstrations. Franklin moved beyond that and began building a hypothesis that lightning is electricity, and then developed an experiment to test the hypothesis."
Franklin observed similarities between lightning and the stuff in the parlor tricks.
Both lightning and electricity looked like light, appeared in forked arcs, crackled, and could kill animals. Franklin described the kite experiment to prove that electricity and lightning were one in the same in a letter to Collinson.
Collinson published the letter in 1751, and European scientists were quick to try the experiment. At least one was electrocuted before a French scientist named Thomas-Francois D'Alibard succeeded in May 1752.
But scientists in England and Belgium had done the experiment before Franklin. News was slow to reach the New World, and Franklin probably was unaware that others had beaten him to the punch, according to Lopez.
Franklin planned to test his ideas about lightning not from a kite but from the steeple of Philadelphia's Christ Church, then under construction. By spring of 1752, the steeple was still unfinished, and Franklin, growing inpatient, decided to use the kite. The experiment took place sometime in June 1752, with the exact date never recorded.
Franklin and his son William were the only witnesses. Everything known about the actual experiment appeared in an account published 15 years later by Franklin's friend Joseph Priestley, the British chemist who discovered oxygen. Franklin read the account before Priestley published it.
It was the classic "never-try-this-at-home" experiment. The Franklins escaped with their lives because lightning never actually struck the kite. Rather, it encountered small amounts of electricity collecting in the storm clouds.
The kite carried a wire intended to attract electricity and channel it down the string to a metal key. By some accounts, Franklin touched the key when he saw threads on the string stand on end, signaling the presence of electricity. A spark jumped to his finger, proving that lightning and electricity were one and the same.
The lightning rod consisted of an iron rod attached to the top of a building, connected to a wire that carried lightning strikes harmlessly into the ground. Franklin's lightning rods sprouted in Philadelphia, New York, Boston, Paris and London.
Franklin's discovery that lightning was a huge electrical spark had immediate practical and scientific impacts.
"He went from an idea, to proving the idea with an experiment, to applying the experimental results in designing a lightning rod to protect property," Lopez noted.
Distributed by Scripps Howard News Service, www.shns.com.